Portable load hoisting device



R. o. PITMAN ET AL 2,717,701

PORTABLE LOAD HOISTING DEVICE Sept. 13, 1955 3 Sheets-Sheet l Filed Nov.6, 1951 INVENTORS: RAYMOND O. PITMAN AYMOND F PITMAN ME {M4 ATTYs Sept.13, 1955 R. o. PITMAN ET AL PORTABLE LOAD HOISTING DEVICE 3 Sheets-Sheet2 Filed Nov. 6, 1951 IN V EN TORS.

N m N n AA w MM A En PP J F DD /A N 0O WM AM RR 3 Sheets-Sheet 3 mflINVENTORS R MOND F. PITMAN BY RAYMOND o. PITMAN Sept. 13, 1955 R. o.PlTMAN ET AL PORTABLE LOAD HOISTING DEVICE Filed Nov. 6, 1951 iJ'nitedStates Patent 2,717,701 PORTABLE LOAD HOISTING DEVICE Raymond 0. Pitmanand Raymond F. Pitman, Kansas City, Mo. Application November 6, 1951,Serial No. 255,024 2 Claims. (Cl. 212--35) This invention relates to aportable load hoisting device and particularly to a remotely controlledhoisting crane adapted to be mounted on a wheeled vehicle.

One of the principal objects of the invention is to provide a remotelycontrolled hoisting crane which may be moved laterally and horizontallyby hydraulic mechanlsm.

Another object of the invention is to provide a hoisting crane adaptedfor mounting on a vehicle frame and having vehicle stabilizing memberson either side.

A further object of the invention is to provide a hoisting crane whichis raised and lowered by a single-acting hydraulic piston mechanism.Still another object of the invention is to provide a crane having aload lifting pulley which is always positioned in the direction of theload stress.

These and other objects and advantages of the invention will become moreapparent upon consideration of the following description taken inconjunction with the accompanying drawings in which:

Figure l is a perspective view of one embodiment of this invention asmounted on a truck frame;

Figure 2 is a diagrammatic view of certain essential parts of the deviceof Figure 1 according to the invention;

Figure 3 is an elevational view of one embodiment of the inventionwithout boom rotating pulleys and cable and without a load lifting winchand cable, as viewed from the front of the vehicle; and

Figure 4 is an enlarged exploded view of the pulley mechanism attachedto the end of the boomin Figure 1.

According to the inventionthere is now provided a portable hoistingdevice adapted for mounting on a vehicle and comprising hydraulicallyactuated means for rotation of the boom through an angle ofapproximately 180 and a separate hydraulically actuated means adaptedfor raising and lowering the boom. The invention further provides aplurality of extensible supports adapted to extend from the triangularframe member to engage a solid supporting medium, such as the ground,and thereby to prevent tipping of the vehicle when the boom is extendedfar over the side. A novel arrangement is provided at the free end ofthe boom for maintaining the load lifting pulley always in the directionof the load stress.

A boom bridle is employed to support the boom tip in such a manner as toreduce the end moment at the tip and thereby to prevent bending of theboom at its fully extended position.

Referring to the drawings in greater detail it will be seen in Figure 1that the portable load hoisting device 16 is mounted on a vehicle frame12 in any suitable manner as, for example, by means of the bolts 14. Thedevice is compact enough that a truck bed 16 may be mounted on the frame12 behind the device.

The portable load hoisting device 10 is comprised of a pair of A-frames18 and 20. The A-frames are secured to the vehicle frame 12 and arejoined at the apices by means of the ridge rail 22. The ridge rail 22 iscomprised of a pair of angle irons having a space therebetween in whichare mounted four sets of pulleys 24, 26, 28 and 39. The A-frames arefurther supported upon each other by means of the transverse element 32and a corresponding element connecting the opposite legs of theA-frames. A box-like frame 34 is adapted to contact the inner sides ofthe A-frame and to be supported on the truck 2,717,781 Patented Sept.13, 1955 frame 12. A projection 36 extends from the box frame 34 and issupported from the truck frame by the members 38. The projection 36carries a bearing member 40 upon which is positioned a vertical mast orupright member 42. The upper end of the upright 42 is pivotally mountedin the ridge rail 22 in such a manner that the upright 42 is axiallyrotatable between the two supports.

A boom 44 is attached at one end to a yoke 46 which in turn is securedto a bull-wheel 48. The yoke 46 is pivotally mounted on the bull-wheel48 so that the boom 44 may be raised or lowered without afiecting thehorizontal alignment of the bull-wheel. The upright 42 is rigidlysecured to the bull-wheel 48 for axial rotation therewith, the rotationof the bull-wheel being effected by means of a cable 50 which contactsthe grooves in the bull-wheel and extends over the pulleys 52 and 54.The cable 50 is fixed at the two ends thereof in a conventionalarrangement. The pulleys 52 and 54 are mounted in brackets 56 and 58which in turn are mounted on rods 68 and 62 (Fig. 3) connected at theirinner ends to a piston (not shown) which is adapted to reciprocate inthe horizontally positioned cylinder 64. The addition of fluid underpressure to either end of the cylinder 64 will result in a movement ofthe piston and corresponding movement of the pulleys 52 and 54. Thecable 50 will be moved and will cause the bull-wheel 48 and the boom 44to swing laterally about the axis of the vupright 42.

Attached to the ridge rail 22 is a vertically positioned cylinder 66(Fig. l). The piston 68 is adapted to move axially within the cylinder66 and to carry with it the set of pulleys 78. Fluid under hydraulicpressure is fed to the cylinder 66 through the hose 72 which isconnected at its other end to a pump 74 (Fig. 3). Hydraulic fluid is fedto the cylinder 64 through the hoses 65 and 67.

Referring to Figure 2 wherein the arrangement of the various cables isshown it will be seen that the pulleys 70 on the end of the piston 68cooperate with the set of pulleys 24 on the ridge rail 22 in a sort ofblock and tackle arrangement. The cable 76 is threaded through each ofthe pulleys 70 and 24 and engages the pulley 30, the pulley 78 on theupright 42, and the boom supporting pulley 80. Then the cable 76 issecured to the ridge rail 22 by a suitable clamping means 82. From thediagram in Figure 2 it will be apparent that an advancement of thepiston 68 will increase the distance between the pulleys 70 and 24 andwill take up some of the cable 76, thereby raising the boom 44.Similarly, a retraction of the piston 68 will result in a lowering ofthe boom 44.

One end of the cable 76 is secured to a small handoperated winch 84 insuch manner that the cable may be taken in or payed out to compensatefor shortening or lengthening the boom 44.

Fluid pressure is supplied to the horizontal cylinder 64 and thevertical cylinder 68 from a hydraulic pump 74 (Fig. 3) which is adaptedto be driven by the pulley 86 which in turn is connected to any suitablepower takeoff (not shown). A reservoir is provided to hold excess fluid.Suitable controls 88 are provided on the pump 74 in order to regulatethe flow of fluid to the pistons 64 and 66. Suitable remote controls maybe attached to the controls 88 and may be located at any convenientplace on the vehicle. The arrangement is such that the pistons in thetwo cylinders 64 and 66 may be advanced or retracted independently ofone another thereby providing a maximum degree of control over thehoisting mechanism.

The actual hoisting mechanism is conventional in design and comprises acable 90 (Figure 2) which is threaded over an arrangement of pulleys andis adapted to be Wound or unwound on a conventional winch mechanism 92.The winch 92 is powered from the vehicle "ice motor 94 in a manner wellknown in the art and constituting no part of the invention.

In Figures 1 and 3 the arrangement of extensible supports which operateto stabilize the load lifting device are shown. In Figure 3 there isillustrated a pair of channels 96 and 98 which are secured to the rearA-frame 20. The element 168 is adapted to pass through channels 96 and98 in alignment with the leg of the A-frame 20. A pin 162 is adapted tobe inserted through aligned openings in the channel 96 and through acorresponding opening in the member 18th when the unit is in retractedposition. A series of openings 104 are provided near the upper end ofthe member 160 and one of these will receive the pin 102 when the member1% is in extended position. A suitable foot 106 is provided at the lowerend of the member 1.130 in order to maintain broad contact with asupporting surface. The extensible support is shown in fully extendedposition in Figure 1 with the foot 106 resting on the ground or on otherprimary supporting means.

The usual arrangement for the free end of the boom 44 is illustrated indetail in Figure 4. As shown therein the boom 44 has a bracket 188firmly attached to the end thereof and held by means of the bolt 116. Abridle comprising two rods 112 and 114 is adapted to be secured to thebracket 1% by means of the bolt 110. At the opposite end of the rods 112and 114 there is provided a bracket 116 which supports the pulley 80. Atthe underside of the bracket 168 there is provided a pair of projections118 and 128 which are adapted to embrace a bracket 122 in looseengagement so that the bracket 122 may rotate about the pin 124. Theload lifting pulley 126 is attached to the bracket 122. By thisarrangement it has become possible to lessen the strain on the pulley126 and the cable 96 because the bracket 122 and the pulley 126 are freeto swing so that they will always point in the direction of the load.Lateral stresses are eliminated and the life of the pulley 126 and theCable 90 are substantially lengthened.

It is seen in Fig. 2 that there is a set of three movable pulleys 76secured to piston 68 and a set of three fixed pulleys mounted on theridge rail 22. There are also a pair of pulleys 28, a pair of pulleys 30on the ridge rail 22, and a single pulley 26.

Thus, the first cable 90 is secured at one end thereof to the firstwinch 92 and passes over pulley means on ridge rail 22, which includesone of the pulleys 28 and one of the pulleys 30. Cable 90 also passesover the load lifting pulley 126 on the outer end of boom 44.

The second cable 76 passes over both the set of movable pulleys 7t? andthe set of fixed pulleys 24. One end of cable '76 is attached to thesecond winch 84 and the opposite end thereof is fixed by the clampingmeans 82. The boom supporting pulley 80, having means 112114 connectingthe same to the outer end of boom 44, also receives the cable 76. Theadditional pulley means on ridge rail 22 which receive cable '76,includes pulley 78, the other pulley 31), pulley 26, and the otherpulley 28.

An important feature of this invention resides in the fact that the loadlifting device may be raised or lowered independently of the lateralswinging of the boom, or if desired, the boom may be swung and lifted atthe same time. The hydraulically operated means for raising and loweringthe boom operates chiefly to fix the height of the boom, but it may beused for the lifting of light loads. The boom may be adjusted to variouslengths by wellknown methods since it is of the telescoping type and itis contemplated that such an adjustable boom will be employed. Thehydraulically operated cable for raising and lowering the boom may beextended or retracted very easily to adjust it to different boom lengthsby means of the hand-operated winch 84.

From the foregoing disclosure it will be apparent that there is nowprovided a portable hydraulically actuated hoisting device which iscontrollable and movableboth laterally and horizontally by hydraulicmeans. This nism including a first cable, a load-lifting pulley on theboom and pulley means on the support, both receiving the cable, and afirst winch on the support receiving one end of the cable; hydraulicmultiplying gearing separate from said mechanism for swinging the boomon said axis, said gearing including a hydraulic cylinder mounted on thesupport. a vertically reciprocable piston in the cylinder, a set ofmovable pulleys secured to the piston, and a correspondin set of fixedpulleys secured to the support above the cylinder; a second cablepassing over the set of movable pulleys and the set of fixed pulleys; aboomsupporting pulley having means connecting the same to the oppositeend of the boom; a second winch mounted on the support; and anchoringmeans securing one end of the second cable to the second winch, saidsecond cable extending from the second winch to the set of movablepulleys and from the set of fixed pulleys over the boomsupportingpulley, the opposite end of the second cable being attached to thesupport whereby, upon downward extension of the piston from thecylinder, the set of movable pulleys is lowered away from the set offixed pulleys and said opposite end of the boom is raised as the boomswings on said axis.

2. In a hoisting device, a support including a pair of spaced, uprightframes and a ridge rail joining the frames; an elongated boom pivotallymounted at one end thereof on the support for swinging movement on ahorizontal axis; hoisting mechanism including a first cable, aloadlifting pulley on the boom and pulley means on the support bothreceiving the cable, and a first winch on the support receiving one endof the cable; hydraulic multiplying gearing separate from said mechanismfor swinging the boom on said axis, said gearing including a hydrauliccylinder mounted on the support, a vertically reciprocable piston in thecylinder, a set of movable pulleys secured to the piston, and acorresponding set of fixed pulleys secured to the ridge rail above thecylinder; at second cable passing over the set of movable pulleys andthe set of fixed pulleys; a boom-supporting pulley having meansconnecting the same to the opposite end of the boom; additional pulleymeans mounted on the ridge rail; a second winch mounted on the support;and anchoring means securing one end of the second cable to the secondwinch, said second cable extending from the second winch, over saidadditional pulley means to the set of movable pulleys, and from the setof fixed pulleys, over said additional pulley means and thence over theboom-supporting pulley, the opposite end of the second cable beingattached to the support whereby, upon downward extension of the pistonfrom the cylinder, the set of movable pulleys is lowered away from theset of fixed pulleys and said opposite end of the boom is raised as theboom swings on said axis.

References Cited in the file of this patent UNITED STATES PATENTS929,168 Robertson July 27, 1909 1,254,804 Holmes Jan. 29, 1918 1,338,161Scott Apr. 27, 1920 1,551,426 Pavella Aug. 25, 1925 2,559,733 Pitman etal. July 10, 1951 2,602,551 White July 8, 1952 FOREIGN PATENTS 116,856Australia Apr. 16, 1943

